


Practical magic

by LetheAfterDark (LetheSomething)



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Anal Sex, Blow Jobs, Light Bondage, M/M, Porn with Feelings, fluffy powerplay, questionable use of black magic
Language: English
Status: Completed
Published: 2019-11-03
Updated: 2019-11-03
Packaged: 2021-01-21 04:00:53
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,878
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21293291
Author URL: https://archiveofourown.org/users/LetheSomething/pseuds/LetheAfterDark
Summary: Felix tries out a new use for an old spell.
Relationships: Sylvain Jose Gautier/Felix Hugo Fraldarius
Comments: 3
Kudos: 121





	Practical magic

**Author's Note:**

> With a mortal savant and a dark knight, this was probably inevitable.

A single coil of black winds its way around the tip of Sylvain's finger. He watches with rapt attention as it tentatively stops for a moment, a vine searching for its next foothold.  
"Ok, that's awesome," Sylvain says. "Where did you learn how to do this?"  
It isn't a plant, not really, though his brain struggles to find something else to compare it to. The thing is an inky black, with shifting hues of blue and purple that remind him of Felix's hair, and it has a viscous quality to it as it grows, slowly crawling down the back of his hand.  
Black magic, he's fairly sure, but he can't say that he finds it unpleasant.  
The tendril feels warm in the coolness of their room, and it pulses softly with an energy he's never seen before.

"Doesn't hurt?" Felix asks, his eyes lit up by the flickering glow of his magic.   


"Nope. Nothing I can't handle," Sylvain grins, as the thing winds itself around his wrist.

"Good," Felix says, and with a flick of his right finger, the tendril moves up, pulling Sylvain's hand with it.

"Woah!"  
Sylvain, almost instinctively, tries to resist. He tugs at it, once, and again a little harder, but to no avail.  
"This is pretty strong," he concedes.

"Of course," Felix nods. The edges of his mouth curl up a little, in a way that makes Sylvain's heart ache for the simple rarity of it.  
"I wouldn't waste my time on anything less."

*

Felix sees that his lover is mostly amused by the current circumstance, and decides he may as well up the stakes.  
He wills the spell to travel up Sylvain's arm, to his shoulder, where it splits and moves, one to his other arm, the other down his exposed chest.  
He'd come upon the spell ages ago, in one of the weirder books in Garreg Mach's library, the ones all the way at the back. It had seemed useful at the time, the kind of thing a lone agent could employ to bind and enemy for interrogation.  
As it turns out, he never needed it. Not in combat, at least.  
The thought of using it for this sits somewhere between shame and liability, but he can't help but feel a twinge of satisfaction watching the stage play of Sylvain's face pass from awed confusion with a hint of fear, to delight.

Sylvain finally settles on an old favourite, a lascivious grin.  
"So hey, what do you intend to do with this new power of yours?" he asks perfunctorily.

Felix clicks his tongue.  
"What do you think?"

Sylvain chuckles, his half-smile more telling than even he probably knows.  
"It's just that I'm feeling a little exposed here, friend."

"Nothing new for you, then," Felix says, taking a step forward and ignoring the other's mock-hurt huff.  
On his unspoken command, the coils contract, pulling Sylvain's arms down and locking them behind his back.

Sylvain lets out a small, startled breath.  
"Oh."

Felix closes the gap with his lover, whose eyes are still wide in wonderment at the new position he finds himself in, and touches his shoulder.  
Sylvain turns to him and leans his head down.  
It's a habitual gesture by now, and it would be endearing if it wasn't so embarrassing.  
Felix kisses him anyway, a brief touch of their lips, enough to reassure, but not enough to be satisfying in any way.  
"Do you trust me?" he says lowly.

Sylvain only grins. "Always."

"Good boy."  
And Felix flicks his finger again, the coils pulling his lover down until Sylvain is kneeling before him.

*

Sylvain sits, nothing but the fabric of his breeches between his knees and the cold flagstones of their bedroom, and he ponders Felix's thigh high boots.  
He has a love-hate relationship with the things. On the one hand, he appreciates how they protect the man, how they make him look when he walks down the cobbles of the castle courtyard, sword swinging at his side.  
But he despises them now, when they stand between him and all the parts of Felix he wants to put his mouth to.

The boots shift.  
"Look at me."  
Sylvain angles his head toward Felix's familiar haughty expression.  
"I'm going to ask you to do some things for me," Felix says, and Sylvain relishes in the sight of those cheeks heating up.  
"Do you understand?"

"I do," Sylvain smiles.

"If you disobey, I will…" Felix stumbles over his words. "I may be… harsh."  
He says it as if he hasn't always held Sylvain in the palm of his hand.  
As if to make a point, Felix curls his fingers and the tendrils tighten, briefly, their energy seeming to pulse with higher speed now, a beat not unlike Sylvain's own heart, or someone else's.

"I understand," Sylvain grins.

Felix leans down and runs his thumb over Sylvain's lips.  
He takes it in his mouth, licks it, sucks on it.

"Pervert," Felix mutters.

Sylvain answers by closing his teeth over the finger, biting down gently and suckling before releasing it with a small pop.  
"And you love me for it."

"Tsh," Felix says, but he doesn't stop, doesn't turn his eyes away. He lets his long fingers roam across Sylvain's face.  
He finally settles on taking Sylvain's chin in one hand and tilting it up.  
"Who knew that being on your knees would suit you this much, Margrave Gautier," he says.

Sylvain, eyes twinkling, challenges his gaze.  
"I do live to serve my loyal subjects."

"Then serve me well," Felix says, and begins to undo his breeches.

*

For being bound and on his knees, Sylvain looks a lot more pleased with himself than he has any business doing, Felix thinks, but then, that is nothing new.  
He pulls down his breeches and takes out his member, stroking it a few times.  
It feels unfamiliar and a little awkward, using his left hand, but the look in Sylvain's hungry eyes alone is enough to light a fire in his gut.  
By the goddess could that guy even pretend like he's not enjoying every second of this.  
"Open up," Felix orders, and his lover doesn't even hesitate, smiling widely as he waits.  
Felix gives a short nod and Sylvain leans forward, lips closing in.  
"Good," Felix says, and he nearly chokes on his words when he feels Sylvain's tongue run down his shaft.  
His right hand twitches and the spell flickers, for a just second, until he regains his composure and tightens it again.  
Before him, Sylvain smiles around a mouth full of dick and Felix has to close his eyes to keep his concentration.  
He moves slowly and focuses on the sparks running up his spine, on the slick warmth of Sylvain's mouth, on the tight power in his hand, until he knows he can handle the view again.

Hair the colour of sunset swishes when Felix combs it back. Honey hued eyes look up at him through lowered lids.  
"You're doing good," Felix whispers.  
Sylvain hums in response and the reverberations run a shiver down his legs.  
He grips the redhead's hair harder and begins setting the pace, moving faster now, safe in the knowledge his lover can take it.  
"S-syl-"   
His breath catches in his throat.  
There's something about the view, the pure devotion Sylvain projects, and the sensation of tongue and lips, moisture and heat, that weakens Felix's resolve, even if he wants to draw this out as long as possible.

This is a tiny slice of heaven, even if he will never admit that.  
He feels his legs go weak, his thighs trembling.  
It's no use fighting it.  
He shuts his eyes again and lets go. He allows himself to overflow, the tension leaving him in rivulets of salt.  
He thrusts, too hard, he fears, and grips clumps of copper hair, but Sylvain doesn't complain, keeps going until Felix is spent, still and breathing deeply, swaying slightly on his feet.

The moment passes.  
Felix straightens his back and looks down at the man knelt on the floor, and the mess he made of him.  
Pearlescent liquid spills out of Sylvain's lips, dribbling down his chin.  
Without a word, Felix wipes it away with his thumb, then licks it off his own finger.   


Sylvain cocks his head to the side.  
"Was I a good boy?" he murmurs.

Felix leans down and briefly kisses the smirk off those salt stained lips.  
"I'm not done with you yet," he says simply. "Get up."  
With a slow movement of his right pinkie, the black bonds holding Sylvain's arms shift and retreat, slithering up to pool around his neck.   


Sylvain quirks an eyebrow.  
"You're going to need your hands," Felix says.   


"And why is that?" Sylvain grins.

"Because you're going to fuck me."

Sylvain blinks only for a moment, before his eyes sparkle with sensuous joy.  
"Woof," he says, and Felix shakes his head in irritation as he leads Sylvain to the bed, shedding his own clothes on the way.

*

Sylvain, jaw a little sore, watches Felix remove some of the furs off their bed. The man has casually taken off his clothes, too matter of fact to make it a show, or still not self-conscious enough to realize how powerful a play like _that _could be.  
That's just the difference between them, Sylvain thinks, and he reaches up to touch the collar now pulsing around his neck.  
It's become warmer, he's fairly sure, and the beat inside it runs faster now, an excited 'badump badump' rivaling, but not entirely matching, the beat roaring through is own veins.   


Felix points to the edge of the bed.  
"Sit," he says. "Sit and pay attention. Do not move until I say so, if you know what's good for you."   


Sylvain, intrigued, does as he's told.  
He kneels on the bed, hands clenched into fists and erection now pushing heavily against the confines of his breeches, and watches his lover take off the last of his clothes.  
Felix grabs the small bottle of oil that they keep on the table by the bed and coats the fingers of his left hand in it. He turns to move away but then changes his mind, locking eyes with Sylvain instead.  
Sylvain swallows and sits up a little straighter.   
Felix climbs onto the bed and begins applying the oil.   


It's rare to see Felix quite like this, Sylvain thinks, but he knows better than to comment. He contents himself with sitting back and observing the flutter of Felix's lashes as his eyes close. He notes the tension in Felix's back, muscles tight in concentration. He looks at the fingers, glistening as they move around Felix's ass, slipping into that heat and coating it, just for him, or so he hopes.  
The thought of it aches and the pressure in his breeches builds to painful levels.   


The collar around his neck has become almost unbearably warm, pulsing against Sylvain's own heated skin like a drum.  
Felix opens his mouth and lets out a breath.  
Not long now, Sylvain knows. Be good just a little longer.  
He watches Felix grow hard again under his own ministrations and has to bite his lip to stop himself from rushing forward. There is nothing Sylvain wants more in this moment than to touch his lover, to cover him in kisses and to bite at the sensitive skin between his thighs.  
But somehow, somewhere, he managed to learn self-restraint.

Finally, Felix stops and looks up, a look of mild embarrassment in his eyes.  
His right finger curls and tugs the collar toward him.  
Sylvain grins.   


"I didn't think you'd be able to wait," Felix says as he sits up.   


"So little faith," Sylvain rumbles, and he crawls closer, led by a coil of black.   


"I suppose you've earned a little something, then."  
Felix leans in for another brief kiss but Sylvain reaches out, takes his chin and holds him there for a second, and a third.

"I think I've earned a lot more than that," he murmurs.

"Have you now?" Felix huffs.  
The coil around Sylvain's neck tightens, and he feels himself pull back a little.  
"Did you forget the position you're in? Your tactics are roughshod, Sylvain," Felix sighs. "What idiot storms in unbidden when the goal is this close?"  
Rolling his eyes, he slips open Sylvain's breeches and runs a finger down the length of his dick.  
"Will you never learn to be careful," he says.   


Sylvain can do nothing but whimper at the sudden sensation.  
Only a little slickness remains on his hand, but it mixes with the beads of pre-cum now pooling at the tip.  
It feels… amazing.   


"Someone's excited," Felix hums, his anger cooled as quickly as it came.  
His hand moves in lazy strokes, utterly wrecking Sylvain's already overheated senses.   


"You could say that."  
Sylvain reaches out again to pull him close, and this time Felix lets him.  
Felix's lips linger over his, pressing soft kisses to his mouth, over and over.  
Sylvain pulls him closer still, wraps his arms around his shoulders and buries his face in Felix’s neck.   
"Felix."   


"Very well," Felix breathes, and with a small graceful smile, lets himself sink back into the mattress, pulling the other along with him.  
With newfound freedom, Sylvain hovers over his lover and grins.  
"Turn around?"   


Felix raises his eyebrows.  
"Is that how you talk to me, Margrave?"

"Please?" Sylvain tries, and notes with satisfaction that the other man turns in his arms, seemingly resigned to no longer toy with impatience like a cat batting a dying mouse.  
Catching his breath, Sylvain rises and runs a hand down his lover's back, avoiding two of the nastier scars, before leaning in to place hungry kisses on a piece of exposed neck.  
Patience really was never his strong suit.  
"You ready?" he breathes into Felix's ear.

"Just fucking do it already."

Sylvain can't help but grin. "As you wish."  
He positions himself and slowly pushes forward, whatever resistance there was giving way to a slick heat.  
Below him, Felix lets out a low moan.  
"You ok there?"  
His lover curses and buries his face in a pillow. That's a yes then.  
He moves again, slowly, relishing in the friction, the tension, the frankly divine sparks racing up his abdomen.  
Then he reaches a hand down to stroke the other’s dick.

"No."  
It's a choked sob and it startles him, until he becomes aware that the collar around his neck is shuddering, its pulse as erratic as Felix's hand clenching the sheet with white knuckles.

"Alright," Sylvain says gently, and he places his hands back on Felix's hips, choosing instead to pick up the pace.  
It earns him a small whimper from the pillows, a sound that only eggs him on.  
He rocks into him, steadily, intently, until he can feel himself nearing completion.  
Sylvain leans forward, his mouth close to his lover’s ear  
"Anything else you desire, Felix?" he whispers.   


"Ffff," Felix hisses. "Harder. Just… act like you mean it."

Sylvain hums and places a kiss between Felix’s shoulder blades.  
He pulls back.  
He thrusts. Forcefully.  
The black coil around his neck shudders,   
and breaks.

*

Felix's body is on fire.  
There's a rhythmic throbbing in his gut and a feeling of elation, the kind that no amount of battles can compare to.  
He's quickly becoming lightheaded, and his hand reaches out, wanders down his body searching for release.   


"Will you let me?" comes a sultry voice in his ear.

"Mm," Felix says and he retreats, focusing instead on keeping his body from swaying out of control.   
He wants to meet the thrusts as they come, but it's hard, especially when a large hand closes around his member and begins to stroke him.  
There's a tightness inside him now, that burns to a painful degree.  
"Sylvain."  
The pillow catches his breath, and with it his supplication, but Sylvain already knows.  
He moves, unerring, until Felix comes undone.    
Felix buckles and curses heavily into the pillow, his body shuddering.   
A few moments later he feels a warmth spread through him and the heavy breath of Sylvain fluttering over his back as he, too, slows, and stills.

*

They lie under the covers and furs of their bed, Felix's back resting against Sylvain's chest, their arms entwined.  
Sylvain doesn't know how long it will last before this will be considered too much affection for the swordsman, but he's happy for the closeness until then.  
"So where did you learn that," he rumbles in Felix's ear.   


"A book," he says, simply.

"You should teach me."

"Absolutely not."

"Come onnn," Sylvain whines. "It's black magic, isn't it? I'm probably better at it than you."

"That's exactly why you should never get your hands on this."

"At least tell me where to find the book," Sylvain tries.

"No. And if you keep this up, I'm leaving."

"Not fair," Sylvain pouts.

"Life isn't fair."

"That was fun though," Sylvain grins.  
He gets a soft grunt in response.  
Sighing, Sylvain adjust his arms, pulling Felix a bit closer and placing a soft kiss to his shoulder.  
"Alright," he says, "goodnight."

In the stillness of night, his mind whirls, tallying gestures and colours, materials and likely powers.  
He'll figure it out eventually, he knows.

**Author's Note:**

> Special thanks to @thekuroiookami for proofreading and helping me make sense of the ridiculous amount of pronouns involved in writing mlm smut.


End file.
